Until recently pulses of neutrons could be obtained from plasma generators like those developed in research on controlled thermonuclear devices, from pulsed fission reaction, and from laser created plasma where a high energy pulse of laser radiation is used to heat a target of solid deuterium. It is now also feasible to use pulsed laser radiation to heat the plasma of generators like the coaxial plasma gun to obtain intense pulses in excess of 10.sup.11 neutrons per burst such as disclosed in U.S. Pat. No. 3,766,004. However, it should be pointed out that any method which heats the plasma during a very short time (nanoseconds) produces the same results, and the most intense pulses of neutrons which are obtained from the fission reactors are very expensive and produce radioactive waste.
Absorption of some of the energy of an electron beam by a plasma would increase its temperature and thereby increase the number of neutrons produced by the plasma. When the plasma temperature is increased the neutron production goes up by the ratio of .sigma.v at the final temperature to .sigma.v at the initial temperature. Here .sigma.v is the product of the relative velocity v and the reaction cross section .sigma. averaged over the velocity distribution of the nuclei. For the conditions produced in the plasma gun, doubling the temperature can cause an order of magnitude increase in the neutron yield.
Therefore, it is an object of this invention to provide a plasma generator that utilizes the interaction of an electron beam with a plasma to provide an additive heating effect of the plasma to produce neutrons.
Another object of this invention is to arrange and control the interaction of the plasma with the electron beam such that the electron beam energy is focused onto the very small volume of dense hot plasma of the plasma generator.
A further object of this invention is to focus the electrons from the electron beam source utilizing a pinch tube.
Still another object of this invention is to affect the orbits of the electrons from the electron source as they approach the dense hot plasma by the effects from the fields of the pinch tube.